From AdamCon Wiki

This page describes the "variables" that are associated with pages. Page variables have the form {$variable}, and can be used in page markup or in certain formatting strings in PmWiki. For example, the markup "{$Group}" renders in this page as "PmWiki".

Note: Do not confuse these variables (set and used only in PmWiki pages) with PHP variables. Page variables can be read in PHP with the PageVar() function.

Note that these variables do not necessarily exist in the PHP code, because they have to be determined for a specific page. (However, they are usable in FmtPageName strings.)

There is also the form {pagename$variable}, which returns the value of the variable for another page. For example, "{MarkupMasterIndex$Title}" displays as "Markup Master Index".

Special references

Special referenced variables are used to specify the context of the variable when:

Defines new Page Variable of name $CurrentSkin, which can be used in the page with {$CurrentSkin} (also for Conditional markup). It's necessary to use the single quotes nested inside double-quotes as shown above (preferred) or a double-quoted string nested inside single-quotes like '"this"'.

If you want to have a Page Variable that returns the currently used password (more precisely, the last password entered), you can use